It is desirable that personal care absorbent articles, and especially garments such as diapers, training pants, or incontinence garments, without limitation referred to generically now for ease of explanation as xe2x80x9cdiapersxe2x80x9d, provide a close, comfortable fit about the waist and legs of the wearer and contain body exudates while maintaining skin health. In certain circumstances, it is also desirable that such garments are capable of being pulled up or down over the hips of the wearer to allow the wearer or care giver to easily pull the article on and easily remove the article. Other garment openings such as sleeve or pant cuffs and necklines may benefit from similar elasticizing.
Various schemes for producing elastic waistbands on disposable diapers have been proposed. Diaper waistbands are generally made by stretching an elastomer, applying the stretched elastomer to the diaper components, typically non-elastic in the waistband area, and allowing the elastomer to retract, thus gathering the attached diaper web components in the waistband area. The gathered waistband will then ungather when applied to a wearer, to give the waistband circumference some extension while the elastomer produces a retractive force holding the waistband snug to the wearer.
In a known method of providing elasticized body openings for absorbent garments, U.S. Pat. No. 5,846,232 issued Dec. 8, 1998 to Serbiak et al., teaches the patterned application of elastic polymers between an extensible outer cover and an extensible bodyside liner and the application of solid waist and leg elastomers in a tensed condition to provide for elasticized areas in an absorbent article.
Elastomeric films have been developed which are desirable in several aspects for the manufacture of absorbent garments. As disclosed in U.S. Pat. No. 6,245,050, issued 12, Jun. 2001 to Odorzynski et al., an elastomeric film for use in disposable absorbent articles is taught which is a pressure sensitive adhesive and which provides liquid barrier properties with some vapor transmission. These films are hot melt extruded pressure-sensitive adhesives sometimes referred to as EBA (Elastic Barrier Adhesive).
In another known method of making elastic waist bands, U.S. Pat. No. 4,968,313 issued Nov. 6, 1990 to Sabee, teaches the application of a relaxed elastic element to a relaxed diaper web component which is subsequently drawn or stretched to change the molecular orientation of the fibers of the web and permanently deform the fiber structure to produce a gathered waist band for the garment.
However, the gathered-material waistband arrangements of the known art may apply excessive force to the skin of the wearer resulting in discomfort, red marks on the skin and other undesirable effects. There further remains a need for other methods of making waistbands for disposable garments which provide a more conformable fit to the wearer at the waist and leg openings. There further remains a need in the art to provide ease and economy of manufacture of absorbent garments, especially where such garments are intended to be disposable.
In response to the above discussion, an alternative method of elasticized garment opening construction is provided by the present invention which provides precise localized application of elastomerics to an extendible garment web for providing a tensioning force against distension of the web during a wearing, thereby creating a conformable fit to the wearer at the waist and leg openings, while maintaining ease and economy of manufacture, and adequate performance against leakage. The method may provide for the placement of variously shaped elastomer areas in a variety of orientations on a precursor garment web. The method according to one embodiment of the present invention provides for the printing, extrusion, or spraying application (hereinafter referred to collectively as xe2x80x9cprintingxe2x80x9d) of an elastic adhesive in a liquid or semi-liquid state to create elasticized areas in the leg and waist elastic regions of an extensible backsheet or top sheet. In another aspect of the invention the elastomers are utilized as vapor permeable liquid barrier materials that are flexible. In another aspect, the invention provides for the printing of an untensioned elastomeric material resulting in an elasticized portion of a garment which is not gathered. In another aspect, the printed elastomers serve to reinforce a biaxially extendible backsheet, i.e. a backsheet extendible in both longitudinal and lateral axes of the web. In another aspect, the elastomer serves as the adhesive between the topsheet and backsheet and further provides a vapor permeable liquid barrier.
The person having ordinary skill in the art of disposable diaper manufacture will appreciate that the disposable diaper is generally made up of the layers of a substantially liquid-impermeable backsheet, a liquid-permeable topsheet and a liquid retention structure located between the backsheet and the topsheet. In order to be extendible, any two joined layers must have compatible stretch to the limits of the desired processing parameters. In other words, the combined layers or webs, in those areas where the webs are fastened together, will be limited in the amount they may be stretched by the properties of the layer having the least amount of stretch.
The present invention presents an alternative way of making waistband and leg cuff elements by applying untensioned elastomers to the waistband and leg hole areas of the precursor garment, by way of printing the elastomer onto a web of extensible backsheet or topsheet material during the converting of the webs to a precursor garment web. The waistband and leg area diaper components of the present invention may be inherently extendible in the lateral, or longitudinal, or both, dimensions of the garment. The areas of the web having leg and waist elastomers may be extendible in either of the elastic sense i.e., with recovery; or the extensible sense, with little or no recovery. The elastomer is applied in an unstretched condition to make the elasticized areas of the extendible precursor garment web and to achieve ungathered elasticized waistbands and leg openings, either of which may sometimes be referred to hereinafter as xe2x80x9ccuffsxe2x80x9d. When the diaper is placed on the wearer, the cuffs will be physically caused to laterally expand, thus forming a desirable snug fitting cuff area having expandable dimension and elastic tension.
Also, if areas of the backsheet, or topsheet, or both, are left biaxially extendible in areas where subsequent diaper loading, such as by exudates from the wearer, may make them sag undesirably, the backsheet, or other component webs of the precursor garment, may be selectively reinforced by patterned printings of the elastomer. Such printings may assume various shapes of elastomer, e.g., circular, striped, rectangular, etc., in various patterns on the web.
Generally, an exemplary embodiment of the present invention provides a disposable absorbent article that defines a front waist section, a rear waist section, an intermediate section which extends between and connects the waist sections, a pair of laterally opposed side edges, a pair of longitudinally opposed waist edges, a longitudinal direction and a lateral direction. Elastic waistbands and leg opening are provided in a unique fashion with selected elastic barrier adhesive (EBA) materials providing elastic, liquid barrier, and adhesive properties. Extendible backsheet and topsheet materials are provided as the materials carrying the elasticized leg and waist cuffs to conform to the body of the wearer.
The absorbent article may also include other known components of diapers such as a pair of fasteners located on the laterally opposed side edges in one of the waist sections. In certain aspects, the disposable absorbent article may be provided in a prefastened, pant-like configuration such that the article can be pulled on or off over the hips of the wearer similar to conventional training pants. For example, the fasteners may refastenably attach the laterally opposed side edges in the front waist section to the laterally opposed side edges in the rear waist section to provide the pant-like, prefastened absorbent article prior to packaging the articles.
There are various ways to accomplish the present invention. For example, the diaper outer cover, or backsheet, and bodyside liner, or topsheet, or both, may be constructed to be extendible in the lateral dimension, shown generally herein as the cross machine direction (CD), and assembled into the precursor diaper. An untensioned elastomeric may be printed in the cuff regions of the topsheet or backsheet before joining the two in the diaper making process, i.e., converting the components into a garment.
A first exemplary embodiment of the present invention may include the precursor web having an extendible topsheet and an extendible backsheet with an elastomeric placed between them in at least one cuff area of the precursor garment. The extendible top sheet and backsheet may be elastic or extensible, or a combination thereof, to achieve selectable conformity of the garment to the wearer.